690
LETTERS TO THE EDITOR
2. Tresidder, G. C., Blandy, J.P. and Singh, M.: Omental sleeve to prevent recurrent retroperitoneal fibrosis under the ureter. Urol. Int., 27: 144, 1972. RE: RADIATION-INDUCED BLADDER TUMORS
R. E. Duncan, D. W. Bennett, A. T. Evans, B. S. Aron and H.F. Schellhas J. Urol., 118: 43-45, 1977
To the Editor. Duncan and associates concluded from their study that patients irradiated for cervical carcinoma had subsequent primary bladder malignancies 57 times more often than might be expected. Their 8 patients with bladder cancer do not reveal such a high increased risk. These 8 bladder carcinoma cases observed in 2,674 patients with cervical carcinoma in a 25-year period are compared to the incidence of 5.2/100,000 persons with bladder carcinoma in the white female population. However, the incidence of 5.2/ 100,000 relates to the number of new bladder carcinomas observed in 1 year, irrespective of age. Since the age of patients with cervical carcinoma varied from 43 to 80 years, with a mean of 60 years, and the mean age of patients with bladder carcinoma is 69 years the expected number of bladder carcinomas must be based on the mean incidence of bladder carcinoma in a female population more than 50 years old. In this age group the mean incidence is at least 5 to 6 times higher than in the female population as a whole and can, cautiously, be assumed to be 25/100,000. This estimation is based on the age-specific incidence of bladder cancer in Rotterdam (The Netherlands) and it is not probable that there will be a considerable difference with the situation in Ohio. This corrected incidence must be used to calculate the expected number of bladder cancers in reference to the population at risk. The population at risk is defined by the number of patients with cervical carcinoma who lived long enough to be at risk for postradiation bladder cancer. As the authors mentioned, of the 3,091 patients with cervical carcinoma 1,393 (about 45 per cent) were alive at the end of the observation period. If one assumes that the entry of patients with cervical carcinoma was uniform in the period considered and that the death rate was approximately constant the given data allow a rough estimation of the total number of person-years involved. This quantity is then estimated to be about 20,000 personyears. With the corrected incidence of 25 bladder carcinomas in 100,000 person-years the expected number of bladder carcinomas is 5. Observed were 8 bladder cancers. The minor deviation from the expected number can hardly be judged to be of statistical significance and is in full agreement with the experience in the Rotterdamsch Radio-Therapeutisch Instituut. In an 18-year period (1954 to 1972) 2,772 patients with cervix carcinoma received radiotherapy. All patients were followed during the complete interval. In this population 5 bladder cancers were observed; if one assumes the same corrected incidence as described previously 4 bladder cancers would be expected. We conclude, therefore, that there certainly does not exist a 57 times increased risk of development of bladder cancer in irradiated patients with cervical carcinoma. At most it may be possible that there is a small increased risk but the data do not permit a reliable answer to this question. Respectfully, W. Fokkens and W. C. J. Hop Departments of Documentation and Epidemiology and Bio-statistics Rotterdamsch Radio-Therapeutisch Instituut Rotterdam
to 12 patients who had bladder cancer after irradiation for cervix carcinoma that is similar to ours and currently is under investigation.' 1. Dean, R. J. and Lytton, B.: Re: Urologic complications of pelvic irradiation (reply). J. Urol., 120: 387, 1978.
Editor's Comment. The reply by the authors was sent to Doctors Fokkens and Hop for their information, to which they replied, "We are not convinced by the authors' arguments. We remain of the opinion that one may not compare the incidence of new cases in 1 year with the incidence over a period of 25 years - here is talk of a semantic entanglement concerning the use of the word 'incidence'. On the other hand, we uphold our approach in relation to the calculation of the expected number of bladder cancers. For this calculation one has to proceed from the age-specific incidence, in relation to the involved number of person-years at risk. Based on these considerations we maintain our opinion that if there might be talk of an increased risk, this risk is far much smaller than indicated by the authors." Your Editor then sent all material to an independent consultant, Dr. Nelson H. Slack of the National Prostatic Cancer Project, for his consideration. His comments follow, "I believe that Doctors Fokkens and Hop are correct in their criticism to a point, and the authors also make a valid point in their response, in that one must consider the age distribution of the population at risk, not just the ages of those who had cancer. I would suggest a combination of the 2 points. Fokkens and Hop make the point that the 8 cases of bladder cancer were observed over 25 years from a population base of2,674 and were then compared to an annual incidence rate of 5.2/100,000. The population in the latter situation is in a dynamic state with new births adding to and deaths subtracting from the total. In the paper, however, 2,674 is the initial population at risk and deaths subtract from this over the 25-year period. It is incorrect to divide 8 by 2,674 = 0.00299 and call this an incidence rate to be compared with 0.000052. Fokkens and Hop have estimated the exposed population as 20,000 person-years. Then, with 5.2 as the annual incidence per 100,000, the expected number of cases is 1. The observed number of 8 cases, or 40/100,000, is then 8 times greater than expected. This is far less than the 57.6 times greater claimed in the paper but still enough larger to suggest some risk factor from the radiation." CLEFT GLANS PENIS
To the Editor. Leff and associates recently described a patient with cleft glans penis.' A similar case was described by us, along with a discussion of the suggested embryogenesis of this entity. 2 We agree with the authors that this anomaly is ofno clinical significance in the absence of meatal stenosis, except, perhaps, as it sheds some light on the development of the distal or glandular urethra. Respectfully, Harry W. Herr Division of Urology University of California Irvine, California 92717
1. Leff, R. G., Peterson, R. E. and Drago, J. R.: Cleft glans penis: a case report. J. Urol., 120: 767, 1978. 2. Herr, H. W., Jepson, P. M. and Bischoff, A. J.: Complete vertical cleft of the glans penis. J. Urol., 108: 282, 1972.
RE: SIGNIFICANCE OF PYURIA IN URINARY SEDIMENT
Reply by Authors. To compare the incidence of bladder cancer in women irradiated for cervical carcinoma to that found in the general female population one must consider patients of all ages. Although we have stated that those patients with bladder tumors subsequent to radiotherapy for another pelvic malignancy had cervix carcinoma at a mean age of 60 years and bladder cancer at a mean age of 69 years other patients in the study group who did not have bladder cancer were irradiated at much younger ages from the second decade of life upward. By calculating the expected number of bladder cancers based on a female population more than 50 years old Fokkens and Hop have created an artificial distribution of patients for statistical comparison. Furthermore, we believe that regional variation in cancer trends is important. Attention should be directed
M. McGuckin, L. Cohen and R. B. MacGregor J. Urol., 120: 452-454, 1978
To the Editor. McGuckin and associates rightly acknowledge the value of microscopy of the urine as a rapid test for urinary tract infection but they show that its accuracy can be impaired seriously by an inadequate collection procedure. Many female subjects are unable to produce a satisfactory specimen, despite careful instruction by nursing staff. A good indication that this is so is the finding of vaginal epithelial cells in numbers equal to or exceeding the number of white blood cells seen on microscopy. The finding of many vaginal epithelial cells should alert the practitioner to the distinct
691
LETTERS TO THE EDITOR
possibility that subsequent specimens also may be contaminated and that care should be used in interpreting any findings on culture. Respectfully, Roger Hole North Ormesby Hospital Middlesbrough Cleveland TS3 6HJ, England
To the Editor. I found this article noteworthy and interesting but I have 2 critical comments. by the authors. They indicate tho.t uinitial vvere collected by the to the routine :i:nessenge:r They do not :ceve;:;l the collection for these ,spe,,w.u,:w, the ir,.terva1 between collection and technologist or ce 10" (202 patients) the correlation fo, per cent and for the stained smear it was 90 pe, ,;,h colony counts of 104 (34 patients) the resp";,,ih· cent for the dipslide and 56 cent fer vvith colony counts cf no < Hf '~A.2 v,,ras approximately 93 per cent £~3r for the stained smeaT. must question 'Nhethe:r indicated in :routine scr-eeniEg or evaluaticr:., e"l,rcn if it vi/ere to be 10 per cent m_0re accurate_ Si:ice most infections respond to 3,hnost all anti .. rnedical dollars could be sa-vcd by sirnpl21 sn excellent inex.pensiv2_ the diagnosis of infection. l1ow·faet th.at. the stained s:11.ez_:r) ODo''90 per cent. We agree that more of these prospective :radiological-surgical studies are required. However, we believe that CT scanning has been demonstrated to be a safe, easily tolerated technique for the evaluation of pelvic and renal disease. 2
Respectfully, Sanford P. Temes Section of Urology, Department of Surgery Malcolm Grow USAF Medical Center Andrews Air Force Base, Maryland 20331 1. Bonney, W. W., Chiu, L. C. and Culp, D. A.: Computed tomography of the pelvis. J, Urol., 120: 457, 1978. 2. Seidelmann, F. E., Cohen, W. N., Bryan, P. J., Ternes, S. P., Kraus, D. and Schoenrock, G.: Accuracy of CT staging of bladder neoplasms using the gas-filled method: report of 21 patients with surgical confirmation. Amer. J. Roentgen., 130: 735, 1978.
CONDYLOMA ACUMINATUM
To the Editor. One condyloma acuminatum, two condylomata acuminata but not, please, condyloma acuminata. Yours in the lonely battle for avoidance of elementary errors m the plural of Greek nouns. Respectfully, Fl. de Glanville PD. Box 30125 1-Jairobi, Kenya
LETTERS TO THE EDITOR
2. Tresidder, G. C., Blandy, J.P. and Singh, M.: Omental sleeve to prevent recurrent retroperitoneal fibrosis under the ureter. Urol. Int., 27: 144, 1972. RE: RADIATION-INDUCED BLADDER TUMORS
R. E. Duncan, D. W. Bennett, A. T. Evans, B. S. Aron and H.F. Schellhas J. Urol., 118: 43-45, 1977
To the Editor. Duncan and associates concluded from their study that patients irradiated for cervical carcinoma had subsequent primary bladder malignancies 57 times more often than might be expected. Their 8 patients with bladder cancer do not reveal such a high increased risk. These 8 bladder carcinoma cases observed in 2,674 patients with cervical carcinoma in a 25-year period are compared to the incidence of 5.2/100,000 persons with bladder carcinoma in the white female population. However, the incidence of 5.2/ 100,000 relates to the number of new bladder carcinomas observed in 1 year, irrespective of age. Since the age of patients with cervical carcinoma varied from 43 to 80 years, with a mean of 60 years, and the mean age of patients with bladder carcinoma is 69 years the expected number of bladder carcinomas must be based on the mean incidence of bladder carcinoma in a female population more than 50 years old. In this age group the mean incidence is at least 5 to 6 times higher than in the female population as a whole and can, cautiously, be assumed to be 25/100,000. This estimation is based on the age-specific incidence of bladder cancer in Rotterdam (The Netherlands) and it is not probable that there will be a considerable difference with the situation in Ohio. This corrected incidence must be used to calculate the expected number of bladder cancers in reference to the population at risk. The population at risk is defined by the number of patients with cervical carcinoma who lived long enough to be at risk for postradiation bladder cancer. As the authors mentioned, of the 3,091 patients with cervical carcinoma 1,393 (about 45 per cent) were alive at the end of the observation period. If one assumes that the entry of patients with cervical carcinoma was uniform in the period considered and that the death rate was approximately constant the given data allow a rough estimation of the total number of person-years involved. This quantity is then estimated to be about 20,000 personyears. With the corrected incidence of 25 bladder carcinomas in 100,000 person-years the expected number of bladder carcinomas is 5. Observed were 8 bladder cancers. The minor deviation from the expected number can hardly be judged to be of statistical significance and is in full agreement with the experience in the Rotterdamsch Radio-Therapeutisch Instituut. In an 18-year period (1954 to 1972) 2,772 patients with cervix carcinoma received radiotherapy. All patients were followed during the complete interval. In this population 5 bladder cancers were observed; if one assumes the same corrected incidence as described previously 4 bladder cancers would be expected. We conclude, therefore, that there certainly does not exist a 57 times increased risk of development of bladder cancer in irradiated patients with cervical carcinoma. At most it may be possible that there is a small increased risk but the data do not permit a reliable answer to this question. Respectfully, W. Fokkens and W. C. J. Hop Departments of Documentation and Epidemiology and Bio-statistics Rotterdamsch Radio-Therapeutisch Instituut Rotterdam
to 12 patients who had bladder cancer after irradiation for cervix carcinoma that is similar to ours and currently is under investigation.' 1. Dean, R. J. and Lytton, B.: Re: Urologic complications of pelvic irradiation (reply). J. Urol., 120: 387, 1978.
Editor's Comment. The reply by the authors was sent to Doctors Fokkens and Hop for their information, to which they replied, "We are not convinced by the authors' arguments. We remain of the opinion that one may not compare the incidence of new cases in 1 year with the incidence over a period of 25 years - here is talk of a semantic entanglement concerning the use of the word 'incidence'. On the other hand, we uphold our approach in relation to the calculation of the expected number of bladder cancers. For this calculation one has to proceed from the age-specific incidence, in relation to the involved number of person-years at risk. Based on these considerations we maintain our opinion that if there might be talk of an increased risk, this risk is far much smaller than indicated by the authors." Your Editor then sent all material to an independent consultant, Dr. Nelson H. Slack of the National Prostatic Cancer Project, for his consideration. His comments follow, "I believe that Doctors Fokkens and Hop are correct in their criticism to a point, and the authors also make a valid point in their response, in that one must consider the age distribution of the population at risk, not just the ages of those who had cancer. I would suggest a combination of the 2 points. Fokkens and Hop make the point that the 8 cases of bladder cancer were observed over 25 years from a population base of2,674 and were then compared to an annual incidence rate of 5.2/100,000. The population in the latter situation is in a dynamic state with new births adding to and deaths subtracting from the total. In the paper, however, 2,674 is the initial population at risk and deaths subtract from this over the 25-year period. It is incorrect to divide 8 by 2,674 = 0.00299 and call this an incidence rate to be compared with 0.000052. Fokkens and Hop have estimated the exposed population as 20,000 person-years. Then, with 5.2 as the annual incidence per 100,000, the expected number of cases is 1. The observed number of 8 cases, or 40/100,000, is then 8 times greater than expected. This is far less than the 57.6 times greater claimed in the paper but still enough larger to suggest some risk factor from the radiation." CLEFT GLANS PENIS
To the Editor. Leff and associates recently described a patient with cleft glans penis.' A similar case was described by us, along with a discussion of the suggested embryogenesis of this entity. 2 We agree with the authors that this anomaly is ofno clinical significance in the absence of meatal stenosis, except, perhaps, as it sheds some light on the development of the distal or glandular urethra. Respectfully, Harry W. Herr Division of Urology University of California Irvine, California 92717
1. Leff, R. G., Peterson, R. E. and Drago, J. R.: Cleft glans penis: a case report. J. Urol., 120: 767, 1978. 2. Herr, H. W., Jepson, P. M. and Bischoff, A. J.: Complete vertical cleft of the glans penis. J. Urol., 108: 282, 1972.
RE: SIGNIFICANCE OF PYURIA IN URINARY SEDIMENT
Reply by Authors. To compare the incidence of bladder cancer in women irradiated for cervical carcinoma to that found in the general female population one must consider patients of all ages. Although we have stated that those patients with bladder tumors subsequent to radiotherapy for another pelvic malignancy had cervix carcinoma at a mean age of 60 years and bladder cancer at a mean age of 69 years other patients in the study group who did not have bladder cancer were irradiated at much younger ages from the second decade of life upward. By calculating the expected number of bladder cancers based on a female population more than 50 years old Fokkens and Hop have created an artificial distribution of patients for statistical comparison. Furthermore, we believe that regional variation in cancer trends is important. Attention should be directed
M. McGuckin, L. Cohen and R. B. MacGregor J. Urol., 120: 452-454, 1978
To the Editor. McGuckin and associates rightly acknowledge the value of microscopy of the urine as a rapid test for urinary tract infection but they show that its accuracy can be impaired seriously by an inadequate collection procedure. Many female subjects are unable to produce a satisfactory specimen, despite careful instruction by nursing staff. A good indication that this is so is the finding of vaginal epithelial cells in numbers equal to or exceeding the number of white blood cells seen on microscopy. The finding of many vaginal epithelial cells should alert the practitioner to the distinct
691
LETTERS TO THE EDITOR
possibility that subsequent specimens also may be contaminated and that care should be used in interpreting any findings on culture. Respectfully, Roger Hole North Ormesby Hospital Middlesbrough Cleveland TS3 6HJ, England
To the Editor. I found this article noteworthy and interesting but I have 2 critical comments. by the authors. They indicate tho.t uinitial vvere collected by the to the routine :i:nessenge:r They do not :ceve;:;l the collection for these ,spe,,w.u,:w, the ir,.terva1 between collection and technologist or ce 10" (202 patients) the correlation fo, per cent and for the stained smear it was 90 pe, ,;,h colony counts of 104 (34 patients) the resp";,,ih· cent for the dipslide and 56 cent fer vvith colony counts cf no < Hf '~A.2 v,,ras approximately 93 per cent £~3r for the stained smeaT. must question 'Nhethe:r indicated in :routine scr-eeniEg or evaluaticr:., e"l,rcn if it vi/ere to be 10 per cent m_0re accurate_ Si:ice most infections respond to 3,hnost all anti .. rnedical dollars could be sa-vcd by sirnpl21 sn excellent inex.pensiv2_ the diagnosis of infection. l1ow·faet th.at. the stained s:11.ez_:r) ODo''90 per cent. We agree that more of these prospective :radiological-surgical studies are required. However, we believe that CT scanning has been demonstrated to be a safe, easily tolerated technique for the evaluation of pelvic and renal disease. 2
Respectfully, Sanford P. Temes Section of Urology, Department of Surgery Malcolm Grow USAF Medical Center Andrews Air Force Base, Maryland 20331 1. Bonney, W. W., Chiu, L. C. and Culp, D. A.: Computed tomography of the pelvis. J, Urol., 120: 457, 1978. 2. Seidelmann, F. E., Cohen, W. N., Bryan, P. J., Ternes, S. P., Kraus, D. and Schoenrock, G.: Accuracy of CT staging of bladder neoplasms using the gas-filled method: report of 21 patients with surgical confirmation. Amer. J. Roentgen., 130: 735, 1978.
CONDYLOMA ACUMINATUM
To the Editor. One condyloma acuminatum, two condylomata acuminata but not, please, condyloma acuminata. Yours in the lonely battle for avoidance of elementary errors m the plural of Greek nouns. Respectfully, Fl. de Glanville PD. Box 30125 1-Jairobi, Kenya
